The death toll has now risen to more than 10,000, and a senior United Nations official, Sergio Piazzi, has said that the Turkish authorities had informed him that about 35,000 people - alive or dead - are still buried under the rubble. Another 45,000 people have been injured.

However Mr Piazzi, of the UN's office for humanitarian affairs, said some hope remained of locating survivors.

"Our experience with the search and rescue phase is that there is a possibility of finding people alive until next Monday or Tuesday," he said.

Nonetheless, concern is growing for the health and safety of those who have lived through the quake, with disease the latest threat to survivors.

The fear of aftershocks has persuaded millions of people to camp out in the open - close to the decomposing bodies of those killed in the earthquake.

This threat is compounded by a lack of running water for most people, with long queues for the few portable toilets.

Most of the rescue workers are now wearing masks, and are being immunised against typhoid. Reports are already emerging that cholera has hit some areas south-east of Istanbul.

Further devastation has been reported after a 20-ft high tidal wave in the Sea of Marmara destroyed large areas of the holiday resort of Degirmendere moments after the earthquake on Tuesday.

(Click here to see a map of where the earthquake struck)

The UN Security Council formally offered its condolences to the government and people of Turkey, expressing "profound shock and sorrow at the great loss of human life and the extensive material damage suffered".

Turkey has been sent £8bn in aid, with 2,000 rescuers and 150 dogs working round the clock. The United States has despatched fire-fighting aircraft, ships and disaster assessment teams.

Night of fear

Some estimates put the number of people sleeping outside on Thursday night as high as two million.

An American team prepares to get to work

The figure included not only those survivors who have lost their homes, but also the people living in and around Bursa - whose governor, Orhan Tasanlar, warned people to stay outside for the night.

Turkey's official seismologists had also warned of possible further shocks - but later reversed their position and advised people to return indoors.

Mass graves

Around the city of Izmit, each day brings a succession of funerals.

The BBC's Caroline Wyatt: "One man even called for help on his mobile phone"

The Muslim practice is to bury the dead within 24 hours if possible - and officials are urging swift burial too, fearing the spread of disease from bodies decomposing in the extreme summer heat.

Gravediggers have worked in shifts, night and day.

Often, the new graves are marked with simple wooden markers, names written in ball-point pen.

In Adapazari, one of the worst affected towns, rescue workers buried 963 people in a mass grave. They took pictures of the dead so that they could later be identified by their families.

Damage assessment

The Turkish Government has begun evaluating the cost of Tuesday's earthquake to the national economy.

A Turkish soldier celebrates finding a living survivor

A national business association, Tusiad, said the quake could cost the struggling economy $40bn.

There has been growing anger that so many buildings fell down because no precautions against earthquakes had been taken.

In recent years, officials have turned a blind eye to contractors who have skimped on materials to provide housing for a flood of rural migrants.

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